This invention relates to an apparatus for stacking sheet-like articles, typically postal matter such as postal cards and envelopes.
This type of stacking apparatus is used for, for instance, a postal matter processing apparatus. After the stamps and postmarks of the individual pieces of postal matter have been detected, the postal matter is sorted into ordinary postal matter and special postal matter. The sorted groups of postal matter are temporarily collected in respective stacking apparatuses. The stacked postal matter is manually taken out and sorted by the operators according to the destination.
FIG. 1 shows an example of the stacking apparatus. As shown in FIG. 1, sheet-like articles A are successively supplied by conveyor belts 10 and 11 which constitute an article supplyer into a stacking section 12. In the stacking section 12, the successively supplied articles A are stacked horizontally, i.e., side by side in the upright state, on a floor (not shown). One end of the stack is held by a back-up member 13, and the other end of the stack is held by a guide plate 14. A side wall member 15 is provided to align the forward end of each of the stacked articles. The back-up member 13 is slidably supported by a guide rod 16 and is spring biased by a spring 17 toward the stacked articles A. The guide plate 14 has a curved edge 14a so that the articles can be smoothly received. Each article A is guided by the curved edge 14a of the guide plate 14 as it is supplied from the conveyor belts 10 and 11 through an article supply path 18 to a stacking position in the stacking section 12 to be stacked in the state as shown.
The sheet-like articles A to be stacked have different lengths and are flexible so that they can be easily bent. Therefore, for the articles A to be regularly stacked to remain in the upright state in the stacking section 12, they must be held in a state slightly compressed by the back-up member 13 and guide plate 14. To this end, the spring 17 is adapted to provide a necessary compressing force. However, it sometimes happens that an article cannot be smoothly brought between the guide plate 14 and the outermost article in the stack due to the compressing force of the spring. This is particularly liable to occur when the spring force of the spring 17 is increased with the increase of the number of stacked articles. In another aspect, since the article is liable to be bent, when this occurs the rear end portion Ar of the stacked article will sometimes close the article supply path 18. In such a case, the next article A supplied is jammed, leading to the stopping of the apparatus.